Table 4.
Hazard ratio and 95% confidence interval of breast cancer according to oolong tea, black tea and coffee intake as assessed by baseline survey
| Oolong tea intake | ||||||||
|---|---|---|---|---|---|---|---|---|
| Less than one cup per week | One to four cups per week | One or more cups per day | P for trend | |||||
| No. of cases | 336 | 153 | 76 | |||||
| Person-years | 454,964 | 148,821 | 93,630 | |||||
| Age- and area-adjusted HR (95% CI) | 1.00 | 1.37 | (1.13 to 1.67) | 1.09 | (0.85 to 1.41) | 0.08 | ||
| Multivariate HR (95% CI)* | 1.00 | 1.34 | (1.09 to 1.66) | 0.98 | (0.74 to 1.30) | 0.40 | ||
| Black tea intake | ||||||||
| Less than one cup per week | One to four cups per week | One or more cups per day | P for trend | |||||
| No. of cases | 441 | 111 | 24 | |||||
| Person-years | 557,038 | 140,312 | 24,776 | |||||
| Age- and area-adjusted HR (95% CI) | 1.00 | 1.00 | (0.81 to 1.24) | 1.29 | (0.85 to 1.96) | 0.45 | ||
| Multivariate HR (95% CI)* | 1.00 | 0.84 | (0.67 to 1.07) | 1.30 | (0.84 to 2.02) | 0.80 | ||
| Coffee intake | ||||||||
| Less than one cup per week | One to four cups per week | One to two cups per day | Three or more cups per day | P for trend | ||||
| No. of cases | 161 | 180 | 173 | 63 | ||||
| Person-years | 233,697 | 213,979 | 210,969 | 69,940 | ||||
| Age- and area-adjusted HR (95% CI) | 1.00 | 1.20 | (0.97 to 1.49) | 1.18 | (0.94 to 1.48) | 1.30 | (0.95 to 1.77) | 0.09 |
| Multivariate HR (95% CI)* | 1.00 | 1.15 | (0.91 to 1.46) | 1.12 | (0.87 to 1.43) | 1.22 | (0.87 to 1.71) | 0.26 |
* Adjusted for age (continuous), area (10 public health centers), age at menarche (continuous), menopausal status at baseline (premenopausal women, age at menopause for postmenopausal women (-47, 48 to 50, 51 to 53, 54+)), number of births (0, 1, 2, 3, 4, 5+), age at first birth (-21, 22 to 25, 26 to 29, 30+, nulliparous), height (continuous), BMI (continuous), alcohol intake (non-drinkers, occasional drinkers, -150 (g/week) and 150+ (g/week) among regular drinkers (ethanol)), smoking status (never, past, current), leisure time physical activity (no, one to three days per month, more than one day per week), exogenous hormone use (never, past, current), family history of breast cancer (yes, no), green tea intake (less than one cup per day, one to two cups per day, three to four cups per day, five or more cups per day), oolong tea intake (less than one cup per week, one to four cups per week, one or more cups per day), black tea intake (less than one cup per week, one to four cups per week, one or more cups per day) and coffee intake (less than one cup per week, one to four cups per week, one to two cups per day, three or more cups per day). Models for oolong tea, black tea, or coffee intake did not include these variables, respectively.